Throughout this application various publications are referred to by number in parentheses. Full citations for the references may be found at the end of the specification. The disclosures of each of these publications, and also the disclosures of all patents, patent application publications and books recited herein, are hereby incorporated by reference in their entirety into the subject application to more fully describe the art to which the subject invention pertains.
The ESAT-6 gene cluster region 3 (“esx-3 region”, namely, Rv0282 through Rv0292 in Mycobacterium tuberculosis H37Rv) encodes one of five paralogous Esx (type VII) secretion systems within the Mycobacterium tuberculosis genome, and appears to be present in all mycobacterial species sequenced to date (6). Although the specific substrates of this transport system are unknown, extensive previous work, including both saturating transposon mutagenesis studies and attempts to generate deletion mutants through homologous recombination (4-6), has suggested that the esx-3 region of M. tuberculosis is essential for growth in vitro and cannot be deleted. In contrast, it is not required for the growth of the saprophytic mycobacterium M. smegmatis (e.g. see PCT International Application Publication No. WO 2009/008912, Jacobs et al., published Jan. 15, 2009, hereby incorporated by reference in its entirety). In view of the attenuated virulence and TH1 cytokine profile of M. smegmatis Δesx-3 mutants, it would be desirable if a way could be achieved to generate M. tuberculosis Δesx-3 mutants.
The present invention address the need for attenuated M. tuberculosis mutants and related vaccines based on M. tuberculosis Δesx-3 mutants.